Synchronous buck voltage converters and other switching power supply circuits are used in portable computers, servers, telecommunication devices and various other applications. Source down silicon technology allows high-side die to be stacked on top of the low-side transistor to implement a synchronous buck converter topology in a very simple and cost-effective manner. Furthermore, this technology also facilitates integrating a pair of power MOSFET in a common source configuration for load switch applications. In many applications, electro-static discharge (ESD) protection is important. ESD protection circuits are used to protect power supply components by ESD event triggered clamp circuits or components to safely discharge a protected pad or node. ESD protection diodes can be used to protect the source down NMOS gate terminal against damage during ESD events. Ideally, the breakdown voltage (BV) rating or triggering threshold for a gate protection ESD diode is tailored to the gate voltage rating of the protected source down NMOS device. However, integrating ESD protection diodes using source/drain implants and masks concurrently used to fabricate the protected transistor can lead to difficulty in supporting a wide range of source down power MOSFET gate voltage ratings and sometimes results in wide ESD diode breakdown voltage (BV) distribution, thereby reducing manufacturing yield.